Return error during JoinFiles back to the caller for inspection

pkg/utils/split/split.go

@@ -103,11 +103,12 @@ func splitStreamGoRoutine(reader io.Reader, chunkSize uint64, ch chan Message) {
 //     fmt.Println(buf)
 // }
 //
-func JoinFiles(dirname string, inputPrefix string) io.Reader {
+func JoinFiles(dirname string, inputPrefix string) (io.Reader, error) {
 	reader, writer := io.Pipe()
 	fileInfos, readError := ioutil.ReadDir(dirname)
 	if readError != nil {
 		writer.CloseWithError(readError)
+		return nil, readError
 	}
 
 	var newfileInfos []os.FileInfo
@@ -118,11 +119,13 @@ func JoinFiles(dirname string, inputPrefix string) io.Reader {
 	}
 
 	if len(newfileInfos) == 0 {
-		writer.CloseWithError(errors.New("no files found for given prefix"))
+		nofilesError := errors.New("no files found for given prefix " + inputPrefix)
+		writer.CloseWithError(nofilesError)
+		return nil, nofilesError
 	}
 
 	go joinFilesGoRoutine(newfileInfos, writer)
-	return reader
+	return reader, nil
 }
 
 func joinFilesGoRoutine(fileInfos []os.FileInfo, writer *io.PipeWriter) {

pkg/utils/split/split_test.go

@@ -60,10 +60,13 @@ func (s *MySuite) TestFileSplitJoin(c *C) {
 
 	devnull, err := os.OpenFile(os.DevNull, 2, os.ModeAppend)
 	defer devnull.Close()
-	reader := split.JoinFiles(".", "ERROR")
+
-	_, err = io.Copy(devnull, reader)
+	var reader io.Reader
+	reader, err = split.JoinFiles(".", "ERROR")
 	c.Assert(err, Not(IsNil))
-	reader = split.JoinFiles(".", "TESTPREFIX")
+
+	reader, err = split.JoinFiles(".", "TESTPREFIX")
+	c.Assert(err, IsNil)
 	_, err = io.Copy(devnull, reader)
 	c.Assert(err, IsNil)
 }